Boring bar



Feb. 14, 192s.,

J. MAGIN BORING BAR Filed Sept. 10. 1923 INVENTOR- jon Maty/'14.

ATTORNEYS.

u u Mi til? Patented heb. lll, i923.

w www JOHN MAGJN, OF SOUTH MILWAUKEE, WISCONSIN.

BORING BAR.

appueauon mea september 1o, 192s. serial no. 662,009.

e construction and coi'itaining relatively few and simple parts. c

.it further object ot my invention is to provide `a cutter-bar wherein the cutters an be adjusted to a very considerable extent and yet to a nicety, and can then be locked against movement, the locking' mechanism l y such that it is not easily displaced, and tintherinore serves to lock the cutters Without any sti-iin being; put upon the adjustinpr mechanism.

'lhe chief trouble with all cutter bars prior to ruine, has been the limited range oi" adjust- 1neut,ihich greatly shortens die lite ot' the cutters.

@ther advantages ot the simple design ot my boring` bar will naturally suggest themselves as the description progresses. lt .is Within the province oit the disclosure to iinprove generally and to enhance the utility ot devices of that 'type to Which the invention appertains.

With these general objects in View, the invention resides in the novel. features oit construction, combination and arrangement ot parts which Will be hereinatter more particularly described and claimed, and shown in the accompanying' drawings, wherein:

idigi'ure 1 is a partial longitudinal section ot the boring bar, taken .in the plane oit the cutters, as indicated by the arrows 1 in Figure 2.

Figure 2 is a partial longitudinal section et the boring bar, at right-angles to that olf Figure 1, as indicated by the arrows 2 in Figure 1.

Figure 3 shows, in perspective, the disassembled parts oi" the adjusting and locking` mechanism.

lieten-ing more particularly to the drawings, it Will be seen that 3 represents the iront portion and Ll the rear portion ot the bar proper,

A pair of cutters 5 is adjust-ably positioned in a slot ti in the bar, and have their outer edges T and their 'l'ront edges 8 bevelled tor cuttingjT when pressed against an object as the bar is rapidly rotated.

'lhe saine slot 6 also carries chuck-nuts 9, which are keyed into recesses of the cutters 5 by means oi' projections l1, and which are slidably keyed into recesses 12 oit the slot 6 by means of slidesl. The rear surtace (upper in the figure) of each chuck-nut carries a semi-cylindrical threaded ,groove 14, the two grooves being oppositely threaded. y

The same slot 6 also carries a chuck-screw 15, havinga neck 16 in the middle and having its ends oppositely threaded, so as toengage the threads of the chuck-nuts 9. In one end ot the chuck-screw is a polygonal socket 17.

To the rear ot slot 6 and at right angles to it and partly cutting it, is a .slot 18, carrying` a locating plate 19. This plate has a recess 20 to engage the neck 16 of the chuck-screw 15. The plate is'held in place by a pin 21, passing through a hole 22 in the shaft 3 and a hole 23 in the plate.

The slot 6 carries, tothe front or the cutters 5, a liner 24, Which can be clamped against the front face of the cutters 5, by drivingl taper-pin 25 into a hole 26 of the shaft 3.

A lateral recess 27 of the slot 6 carries a second liner 28, which can be clamped against one lateral :tace of the cutters 5, by means of set-screws 29, which have socketheads.

One end 30 ot the chuck-screw 15 may, it desired, be graduated as a micrometer gauge.

The method of assembling and disassembling` the boring bar is readily evident from the foregoing description of its parts.

Adjustment is accomplished as follows. Knock out taper-pin 25 and loosen setscrews 29. Insert a key-Wrench in one `of the polygonal 'sockets 17 of the chuck-screw 15. Turn until the blades 7 of the cutters 5 are the proper distance apart. Tighten the set-screws 29 and drive in the taperpin 25.

It should be noticed that use oi the chuckscreW enables a much Wider range ot adjustment than would be possible with the conventional Wedge-screw driven between the butts of the cutters. Thus the cutters of my device can be ground down long after the cutters ot the conventional device would have to be discarded.

Also note that the threading,` of the chucknuts is greatly facilitated by having them separate from the cutters, for thus the chucknuts can be made ot softer and more easily Worked metal than the cutters.

Also note that the strain due to clamping the liner 24- against the cutters is taken up by the slides 13 against the recesses l2, instead oit heilig transmitted to the adjusting-screw as in all prior devices ot this class.

Also note the clamping eil'eetof liner 28 against lateral Wobbling of the cutters7 this feature being unique in my device. i

l do not intend to be limited to the particular foregoing enenipliiication ot niy invention, hut rather intend to avail inyscli ot all equivalents.

I claim:

l. In a boring bar, the combination of: a recessed shaft; two oppositely-inoving adjustable cutter-blades therein; two nuts7 one el which is removably keyed to one of said blades by a simple projection and recess, and the other ot which is similarly keyed to the other ot' said blades, both nuts being slidably keyed into the interior ot the recess ot said shaft; a right-and-lelt-handthreaded screw, engaging said nuts so as toy convert its rotation into their translation, and having a constrcted portion; a collar, removably engaging said eonstricted `portion, and slidable into and out of said shaft; pin Ineens lor holding said collar in position; ineans operable upon the l'ront edge of said blades tor clamping said blades against inotion longitudinally ot' said shaft; and distinct means opera-ble upon the side l'ace of said blades, ior clamping said blades against rotation with respect to said shailt about the artis olf said shalt.

Q. In a boringl bar, the combination ol: a recessed sha'l't; two oppositelyanovilig adjustable cuttenbladcs therein; two nuts, one oit which is removably keyed to one of said blades by a simple projection and reci s, and the other ot which is similarly lo?. ed to the other et' said blades, both nuts being slid-ably lteyed into the interior ot the recess olf said shalt; a right-andlelthandw threaded screw, ei'igaging said nuts so as to convert its rotation into their translation, and having a consirieted portion; a collar, removably engaging said eoustrieted portion, and slidable into and out oit said shalt; pin means tor holding said collar in position; nieans operable upon the :troni edge et said blades for clamping said blades against niotion longitudinally et said shalt; and distinct means operable upon the side lace ot said blades, for clamping said blades against rotation with respect lo said shalt about the axis ot said shaft; each of said last two mentioned ineans comprising a liner and nie-ans tor bringing pressure to bear on said liner, whereby each liner serves to prerent loosening ot' its pressure nieans.

JOHN Mrlt'lN. 

